Issue 3 [November]( Special Issue: Development and Evaluation of Sorbent Materials for Environmental Applications ) Polychlorinated biphenyl sorption to activated carbon and the attenuation caused by sedimentHale S.E., Kwon S., Ghosh U. and Werner D., Pages:318-326 DOI: https://doi.org/10.30955/gnj.000716Paper Topic: General Issue: Issue 3Get Full Paper AbstractActivated carbon (AC) is currently being used to treat polychlorinated biphenyl (PCB) contaminated field sediment. In the presence of sediment, the sorption capacity of AC for PCBs can be reduced. In this study, sorption attenuation of AC is investigated using previously published data from 5 sampling sites where reductions in aqueous concentrations caused by AC amendment have been reported. AC-water partitioning coefficients (KAC_clean_water) were determined at a relevant PCB concentration in clean water using polyoxymethylene (POM) passive samplers. Logarithmic ACwater partitioning coefficient values ranged from 7.39 to 9.59 for trichlorinated to pentachlorinated congeners. These AC-water partitioning coefficients were used in a numerical model to predict expected reductions in aqueous concentrations. Results reveal an overprediction of actual reductions by a median factor ranging from 2.5 to 5.6. To obtain an estimate of AC sorption attenuation, an AC-water partitioning coefficient more representative of sediment conditions (KAC_apparent) was fitted via the model based on the observed reductions in aqueous concentrations. On average, median KAC_apparent values of individual PCB congeners were smaller than KAC_clean_water values by 1.08 log units, or a factor of 12, with corrections ranging from 0.1 to 2.3 log units. The main controls on the reduction in sorption of PCBs to AC are PCB physico-chemical properties and AC amendment variables. Generally AC sorption attenuation increased with PCB hydrophobicity and decreased with increasing AC-sediment contact time and AC dose. Eroded plastic pellets as monitoring tools for polycyclic aromatic hydrocarbons (PAH): laboratory and field studiesKarapanagioti H.K., Ogata Y. and Takada H., Pages:327-334 DOI: https://doi.org/10.30955/gnj.000675Paper Topic: General Issue: Issue 3Get Full Paper AbstractThrough transportation accidents or intentional releases, plastic pellets (small granules 1-5 mm in diameter) are widely distributed in the ocean all over the world. These pellets accumulate organic pollutants and can be used for the determination of diffusive seawater pollution. Pellets demonstrating a certain degree of erosion are expected to have enough contact time with the water pollutants and thus, reach sorption equilibrium with the water phase. In the present study, eroded pellets collected from Greek beaches, were separated into polyethylene (PE) and polypropylene (PP). Polycyclic aromatic hydrocarbons (PAHs, i.e. naphthalene, phenanthrene, and pyrene) were used as model compounds to study the uptake kinetics into these eroded pellets. Naphthalene uptake demonstrates similar kinetics in both eroded PE and PP. Phenanthrene and pyrene uptake demonstrates slower kinetic rates by eroded PE than by virgin PE and similar kinetic rates by eroded and virgin PP. These observations are then used to evaluate PAHs measurements in pellets sampled from two sampling sites in Saronikos Gulf. It is concluded that seawater in Loutropyrgos beach is polluted by PAHs more than seawater in Aegena island. PAH pollution in both sampling sites is of pyrogenic origin. Pages« first ‹ previous 1 2
